SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78fba655e2bd545e007c11d95bd630515d27c08bb1bfd3d003c1882ae274ff15' 
  AND token = 'VHQIZEg6krPLgEbUr7UYj6IehvgNgyHQAdGqRGuwTVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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