SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c36d52bad397152e0cf1de904ac094fdfba189459da7e4c2761b18a4c803be8e' 
  AND token = 'IifgLhkWv3XGfqV5fIKfGlZPFEeSraGerfo/bdXgpk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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