SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7bed3f552d76545e05699b20113f7f14bf33c81d854e90720f975887cc08b6f' 
  AND token = 'M73Jijy2yw1gMbiP5Uo7Mtp51JZ/mVq95CuxA3rh6Tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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