SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af3339a53b356283def784fcfb5634c2cdac84703da23a500f215bdb49052d82' 
  AND token = 'gYp5+GGcUMY2T4xtKEBJmlsIcQFAnbEnXWYmuTkZ/fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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