SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63a8e8af7252e700b9232081027ff7c03cb4df9c5eb18664f3af57c32795d083' 
  AND token = 'N5GBXyTP8R6m3609OWCks7M+LUAVuRsturEVpT9+Gzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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