SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec1f445bfd4c9120440026483437d7cc23b7552cd6eb26629f43e9ee690e011e' 
  AND token = 'xdUnVQjtByF3CvUsIAR/AS754d1ndrj55jQV6yYVzbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}