SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859840b114a4779fed0eb89c713377d89f10d9261d8732043afc308076bc3ed7' 
  AND token = 'jlwk3mmwZlt8DOAoqT6HRGHOaeSlCcc/krcxpOZZDhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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