SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7842bfeb0b95cec6eede1b09a532c747dcfe5804ffa5adebb56a987d6830bf0c' 
  AND token = 'D7ZaufRQWItrHF1bMi0b1iMsX4/DFQipzFLPQKPaWOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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