SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bce2bea618a5590e69149451d64660ba2ff438b1b11f47caaa3b63f1010f56e' 
  AND token = 'yS3VyPmEoUwVQQex5zOiLf/jNvCdSv8OcDAnb3TXBUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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