SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003589b9a7819222f176391131030bdc22f12f97ce08d4021f8444c4144586ca' 
  AND token = 'QpCjEyYAq4zdblLUzKgv/M6C9eNUmJn93myI+aC4dgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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