SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf52e70f499b72d75d73206ce93f13a3762d95433d6b752d59f3141f0737c810' 
  AND token = 'Gy4Q5voynSX3DpgXwQISQJJPDK/x/TtzhPjeEltjbZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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