SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa74af3d3780cc3317881a2f10265f94a280d8d6f2a39d93004255c19971b24' 
  AND token = '2JKZmWOKV4tZm1tIsVyWBPkykmyU5r6jMh0WwhiaPT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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