SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '348bea588263fb5fdf5d7e809b05617401e71fae124a30e17203a3ed202935c2' 
  AND token = 'Jhfnc8TIQ24LG6eMlwqW8y80gzvgosNvWMl9F6mxkp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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