SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c7939a8033f004ebc3c1b47b70949d7386c4fdff8afb24b26c4c2ed15e95038' 
  AND token = 'eXax3VXSDJG/sk72hALjDhIOvr66XWpv+rwqh6vTirE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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