SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b062dd15c7c8f092fdda826680e31e7479d92096a86aaa1fb21d0db16ea51f2' 
  AND token = 'tpgj81lKTQDytEEe2QhVENoCTUQgkevV1jmhZJhf7Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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