SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57fc6a68f335eafc17d47bb78b008cf2655726ae57300626a7f9ed3a3e33b96' 
  AND token = '4WJ3qDstk7nOh0p4uDFdXBUpuCLxxHzj+7EFhbSpSKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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