SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '750d3c87a6c819267ca82df9306638fe5f49b510a6b2f8680aee7726be05dc05' 
  AND token = 'OH+JfaXJEZEpOXMN1DwjRDk0KZe9iZtBEpXWtpzzESI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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