SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a273535f9ac41188015c2ce2a15a9d03cc123a4a3fc7855bdaf0b306f049802' 
  AND token = 'IY4ZZoyqQ3MmvkzP2L7glvdQEv7wL187DCufNKGNFD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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