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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f48857d9aba2e78e77125c16d07fd6d0499307e4ca63b0dde6bb1c8cb1f3d71f' 
  AND token = 'n2Qq1iCtDpTgLldlcpNLxN03PUKsYR+pPH1Ubu3eIcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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