SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50339a4a81446f8edd068cb2426d702cad0f52a42f68c7f313c503e9fccb659e' 
  AND token = 'pQ9P72Hy+uKkIhHU9qBtl4x5J3WT9J3+N+o6fCHGZUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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