SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd54240a53651af714489d8540331274d8c9ba0e13b69ff955cd1571a3203073d' 
  AND token = 'pHHL6armNyCZfPxeZMF8bChy5hyvimsmryRkuqYC4k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}