SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8f6fec0ef2d7a13297013844ff5f58adf0537cb5ced90ce158edce663da2a1e' 
  AND token = '/XZjZML2nPcVV+qmEkSGDlp+j35UbDCsZ5TxIG1I+BY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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