SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cfd3363821f87febb5f9a005b6546ad2c3f0862850f444d7167f09250556367' 
  AND token = 'exYsBe/xK20Eiiz+fyewKTXuWFiVYX92h+OR8V5/bvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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