SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b76ce5e24dc1ea19b17ee61df6ec12590caae7dfd22899812197fb654a9eba2' 
  AND token = 'ZdFp0YjgmCGgFrVsP88FqrdFiSf9ZhJPwO1YmkYVRoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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