SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe72e35b83264dc7b8db40e5e14963f05c94f92737f47a75b12889ea9f65c3c' 
  AND token = 'ZA2SwYQDHO+UDRnTXfqpoUkW+PC/pPm2SCNPQkoKyTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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