SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd139fb0ba5c4d725d3dc91fa17e75bcf1ba1a2dfada6da243c325647c62ae5f1' 
  AND token = 'PVhBOUEKDTYQDv4uyq8rynI5WNzLQJBv9WcOR9kjLfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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