SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b065ad438f09174f6f22fb83c0c580663eaa94fb90768bdde9f7154a0932e1' 
  AND token = 'bjrJR/B2QwFrIMnHTvTqNzQ1hcuA8cPNeSD9HZckPyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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