SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '171d6d02a962027780414ff6dfe5f904713c4eeaa311d1c19ccf398073f9cab1' 
  AND token = 'BHvb4OBw3TkdxdYinF4evXZruwRq8rT4a+5PLgSA9QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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