SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f4b265cdf959706759546c7952359a1893ed609477e457e5606624719e09ee7' 
  AND token = 'nWt38Wyw29uvZOjb0P975KQb7gwQQSSOtCQSDKXRj2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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