SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42e2710aa35a61d0c148319c03224a9751f868c03c1b5ae56c84add999b57884' 
  AND token = 'n9YGNh8l7ZxD0KJ6mB+8Uhw5uRb2Lwv5W6gUSKhEiIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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