SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdb99f8cdb221547959ff85b74e8d92bd37db68ec0fd02594b1387355fae7d72' 
  AND token = 'PPTnVfgmIvMV4kfr5UVjhBEUhhnzHDD3BhNBj6FVWPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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