SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ba97980f185a6f73f4cea8f980d1c75d8354a5357b5dc41ff5a03a94d8aa88' 
  AND token = '54j/9GDqHTNXjdYpoE+3GjZtOFrSyxJjPkrdkeyTw88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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