SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e60ec2e4f630ccaf76aa7e2304b9963b7e9846e9c7134541cedcaf4befbb5f16' 
  AND token = 'KgSuXXJKOZ0exP3GLFElEyzQVXtwk/lgexsOtVcaG8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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