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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6602c3b4e8da3cfb30b42d365fd323e021dd5ff3995aa059c26f987491e984c9' 
  AND token = '4Nga+7TnJXK83oSRKI4aV75Lk3xbAvKDJkjQrtnYYmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}