SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e56113fd842744744ad318393c4f90ec7825be5ba0274bd402ca6bdfdde7836f' 
  AND token = 'dKMtW0wvYfeKDG3YXhvaYEFKXVfZBVlSrs0JaazNmac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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