SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2abcf4e5c464d6b4f107a596dacebf2610b300ecdc3d4fc98f407da00b0e294f' 
  AND token = 'f5ZNfnYtm9BUFzh7/94/bLzlGSAioPmaE2QGmmUtPQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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