SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25ba5bb21cc46da6acaaabeed769930ac87a810411fda0b1d823a9a2db988369' 
  AND token = '1QUp7KaeB/ejiTjKp6I9pMYDWwZ86aJrj0JL20GRKJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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