SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39f534b843faf08d2c97a2bcdb878b99f777e1930fabaa418f9f0a0a3db97bfa' 
  AND token = '9l+Hqrp2upV7UzRcxE4ZzKjqJV60F6EC3v/g5Yx6emc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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