SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1aa386755d7ca07d2dc961438e729cf62f50425e98c3b8a6a86e984a011c24c3' 
  AND token = 'EVLHYUMkOp/AwZBveZi15cGlwaDqsgtOKomx/IJQX5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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