SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce4983476bffd0cc44fbed5a2495e25ffd3a5b5b4912daa01f548c6693969ca' 
  AND token = 'GU7gKcz86vI99IFsDoKXQjDZF0CXrOGxqBG/QSyQ7H0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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