SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f46259f6478796803ac702c219206e040adb54941632e571c3ba266ca64d1a2e' 
  AND token = 'Ejq/0WIzkuCvWQtfqQTaIzKiXaocYrsqUNPA4kSv3Sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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