SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b948d378a3c1ae1c31d781f4be57f196e9a0f672198150fe697a0b2fac73c61' 
  AND token = 'ptMRyYoiuqFHGa4yHOVQsnQ/0mRd9+jEFQLlnD7lf6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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