SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950967e846778b6ee265d02be3c2f9db9d8271a8f8caa114067dc55161de9366' 
  AND token = 'u1viVTyZiE3Uh5R246oCLJfuUD4JjmbthQKU+5VzzZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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