SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd95ebf92fc3606b20b862995f5c58fa652ff99559b7b0859c81879426285b9ea' 
  AND token = 'Do5nQTngt+Yk1hkM4kNqNCOKpXx0//KTf3LXkEXxPs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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