SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76c946a4239e073379fd7b8044d8593e1a0f0e58da62970c1ae0c9a62ace7f3' 
  AND token = 'LmPDOXJoafTqCzGtEWXkQnnqmLAtg0Csz5Cb2EhAevg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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