SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c878d61b33b32ba462cf738dbf9f16f99128e51c5d6bf177f43bbd50a4e9d19e' 
  AND token = '59NuWd//UxHNAvKzFDbnmFbsIyeHdQMonddTRohY7VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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