SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d998661f36c2ea9bb2ae732477368c932090bd364db70758b07aff1caa27286' 
  AND token = 'tMgAWQxAxVtkUC8y+bJZhteKjLulcmqQGrQWC2YcMgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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