SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f170b90790f650deac42664869f87979b451b4178ebea299a909dc99ed73a8c' 
  AND token = 'pOtdAaJwcYJ+ZxAlXariQIcebVIqAU93TCpRD6EUUjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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