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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f5cf2a985d45fe4519ddc2772fdbbd2a88b54ac3215f1cf4e84dd10c982e70' 
  AND token = 'kV0HI7Wn/9bwTk7kk00hpoTVpLdQTX5lMZ7xPkDZ3F8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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