SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '243568d2a5664cac16e821fe730397ba6ef0d164ad97139af9917b39a792fccf' 
  AND token = 'Gis+YbXBZmjVmdKKmKIoFDIT64SD2svA2YDHxRQBOxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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