SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4081c6c6964d9a102ea7d4bf19792d4a2186f0aa37673f42f8fc88f058957802' 
  AND token = 'mnrAPomNeirWR6B9jynz1iMvJpLJ1DMyPZY9c666OCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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