SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3268980cd8a3458ef50917259d5046ac79d0818bb08ef2b1553f4fc372ac1a8d' 
  AND token = 'Adbl1Dp42Ctvbbv7GnOuXL8VRIqV4CSYzEBlgdYE2Gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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