SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f23d516ab218777368a15bdf26b9c211087e0b3601158e7f563f6ed04941c1d2' 
  AND token = 'jumrDKyYULTV3egloc9y4dD7dgAYwyE0bByBOhCViIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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