SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e0ea338b59bdfabe84891001a44ccd40540e126aa620c617d65b1118a4b5acd' 
  AND token = 'EWu36DhvYYKgl+nnrLLsbDfVPwq07OtIq7SJczYZMC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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