SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ddc4888d47104951c1d0a322f442cd83cbe19099d0d475d6275bff2448d25f' 
  AND token = 'axzEQdRFPJBDR5rjriwCYWGab2uzyNKjIPm8gSzNgNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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