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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6aac5b95be9011f87e8d45c2eefd8d0a93eeb282ce3e7fa4e354f26259f5b24' 
  AND token = 'c9Ot3lPfG9CMR6wcInpS7P653Qpyz9OJL+EDSSJge4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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