SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48b65db7be6fb7427e1919a2c221b4c5202ef2971668276822c93cf42414cba9' 
  AND token = 'fDLDgrXpPoH3yIcMx2dZEwoApYzn9USZp1rjtfWWrTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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