SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3696b6decbe9884ea1a8ca33b71abaadf44a7c90331a5c8746d1579eab5975aa' 
  AND token = 'O0pvREqbiLndOW1FGrZASgsz13JZvFxepRe7pooxdb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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