SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6204e2583e252bba38e0215f650e623c99394c22dca4b31d100e78808bf95543' 
  AND token = 'BiI8Gsf+N6ItCcrZyKKXw8x1/EbrOerAJgPsOqJ+f1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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