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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7923b96f8ba1d217a9708310176282b42d96636c17e2c3c15eaad9c2fe51d9d' 
  AND token = 'fo7hrWYQLz6GrXNmrZAqJz+7NsisKCsX/UDNFQ2Sc3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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