SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'da76cff73f4ef91ef155f03b693daa47a4ec2c42f24db4c1f628fb653dd3bf79' 
  AND token = 'ndQ9eQcAAE8kKD8UC9aGXn2MDz/FrTl7GzkQLEy7OdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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