SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '885b174628ef27eebc267f05036d81856b883cda33e92438d6d4adb7d3124ad3' 
  AND token = '5NNNaQVS1VkkCltUmSEELzWvzDUfqkvjMLShCM7P0eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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