SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27362c71be0a501555a74a55af374a12b30c8358c27479d096a265a52e1d4d88' 
  AND token = 'DQRinsoU8NKpoK9C9YnUURCsueo3YYN1AfoKg5i3xb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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