SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1b57ce087aee17e01b7921c896f84d09245b140293cd0225b0aecc9b3fd08c3' 
  AND token = 'csYvIIwZgNVqAq62QLiWpQx7FZ1D1v2Aau7idbt5evk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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