SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fba44132d5443f6597333e208cff572fe6e2443ec18f14ac85319c6fd6ecb7da' 
  AND token = 'NurmNwCqm99p2eiKM4mkuAWgtCaqqNaXLQINUVT09x8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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