SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb770ffde84d6d100e2bf7ad406982f7dd0b5939602581730b01d0a86949a2a2' 
  AND token = 'nW6TVaZuQFBZewMOzcL54qGuyktFGghZiKVoJOzNfQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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