SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c250805d4206273cc43a19427cc3dc5a98300ea12bcabddd7461157b68a0666' 
  AND token = 'AWAJsQv2Z7XZb48LQql5CJWvmJg/zYiqoWhwaTQqHYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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