SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e0e50600f37c1af11bd1ebc80a6c7edb565970cf68a44a25af3316bacc025b2' 
  AND token = 'Zj71f33jXEbKocaPfmOogNZgo5WQZvujnd59kJfrMb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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