SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4694b332c8705febccf036196245e92fe4620d4f2de21418e220384a53d4b648' 
  AND token = 'fTcrnfzFwi271RxBe4KW6Mu+d5srYdPeR0WcMFgPRIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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