SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '357b17b463f84e197933f758f345b14c264b528f6d4fde9d6944f6f0375c22d7' 
  AND token = '2IYi5NkXW1oEYwmxSYJDCO6r0hFMjcxfsqKkgygzxIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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