SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '396c5b55bd2a524947ef3fc96684f781785577fa493e05627318624febf239e0' 
  AND token = 'DvnniB4PV8oXvQKz7GJ9noJhObVlPjKfrPMWh4ALHBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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