SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '92efa8246720c8dff774a26e4d3aa07176334a11cf7aff3d009d8b826185d942' 
  AND token = 'l6OlnOiu3/GuFO3cthqcLhD14UmpH782Sni6aQFQdvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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