SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a78943704b8f96e9b15f97e34fdb0fc7c34164e00586b09f16f32e7bc8732518' 
  AND token = 'kmlByyuvUdkNxw6cWf5jHZ9w07haqWnokVO9tdz+Yh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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