SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c079acfbdeed9b39560db7d74a11ab6cfc25619b68267bab177adb2b8fce3dac' 
  AND token = 'oUmfBqUSlSRIFKyTNjhuREIGNmQgOAjIdTcbBcqoDSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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