SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fb3ab9cb9e0c7b747ca1ad4254799e3ce2c6b2f87a0431b2c3b7472321b5333' 
  AND token = 'RgtI5JuyUGyaEkbeqwuAmkWgwN0ngivB7mtzInziXdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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